What are the natural and common protection methods for lithium-ion batteries

Common protection methods are shell protection. In order to prevent air from entering, lithium-ion batteries are encapsulated in a closed container, and in order to prevent external force damage, they are generally equipped with a stainless steel case and an aluminum alloy case. For example, Tesla's electric cars even use titanium alloy protective plates to prevent the damage to the battery container in the use of the car, especially in traffic accidents. The maintenance of the barrier block, in addition to preventing external damage, also prevents damage from the inside of the battery. Generally, in order to prevent the battery's positive and negative poles from directly touching and short-circuiting, there will be a barrier inside the battery. However, in lithium-ion batteries, the barrier also assumes another protective function. When the battery temperature is too high, the gap will be actively closed to prevent lithium from passing through, and then the entire battery's response will be terminated. Then it prevents the battery from being too high in temperature, causing the electrolyte to vaporize and generate high pressure, which damages the battery's sealing structure. Overcharge voltage protection requires not only the air to be isolated, but also to prevent metal lithium ions from leaking from the electrode. Scientists use the nano-space and data lattice mechanism of electrode materials to store and lock the metal lithium ions formed during charging and discharging. In this way, even if the battery casing breaks and oxygen enters, the oxygen molecules are too large to enter these small storage cells, which prevents the onset of spontaneous combustion. However, using an excessively high voltage or charging for an extended period of time after being fully charged will cause a very risky hazard to the lithium ion battery. After the charging voltage of the lithium ion battery is higher than the rated voltage (usually 4.2V), if the charging continues, because the storage cell of the negative electrode is now full of lithium ion atoms, the subsequent lithium will accumulate on the surface of the negative electrode material. Because of the polarization effect, these lithium will form electron transport, form metal lithium ions, and grow dendrites from the surface of the negative electrode to the direction of the lithium. These metal lithium ions without electrode protection are extremely vivid on the one hand, and are prone to oxidative reactions and explosions. On the other hand, the formed metal lithium ion crystals will break through the barriers, short-circuit the positive and negative electrodes, and then cause a short circuit, resulting in high temperatures. At high temperatures, the electrolyte and other materials will crack and generate gas, which makes the battery shell or pressure valve swell and break, allowing oxygen to enter, and reacting with the lithium ion atoms accumulated on the surface of the negative electrode, thereby causing an explosion. When charging lithium-ion batteries, be sure to set the upper voltage limit and overcharge maintenance. Lithium-ion batteries produced by regular battery manufacturers are equipped with such a maintenance circuit. When the voltage exceeds the standard or the battery is full, it will automatically cut off the power. In fact, spontaneous combustion is not easy. It is not easy for lithium-ion batteries to ignite spontaneously under the protection of qualified enclosures, barriers, and circuits. Especially in inorganic materials lithium-ion batteries, for example, lithium iron phosphate batteries, because the battery is not like the ternary lithium-ion battery that uses organic materials, even if there is data damage and short-circuit inside the battery, the high temperature will not make the inorganic material The data differentiates and produces high pressure gas, which explodes and ignites spontaneously. In the experiment, even if the qualified lithium iron phosphate battery is put into the firewood (the temperature of the firewood is lower than 600℃), it will not explode and natural conditions. At the same time, compared with the situation that manufacturers did not fully understand the protection methods in the actual use of vehicles in the early stage of the development of new energy cars, now, after decades of exploration and the practical application of millions of new energy cars around the world, from battery manufacturers to car manufacturers Satisfied experience has been accumulated. The protective strength of the outer shell of the lithium-ion battery has been greatly enhanced, even in the case of a serious traffic accident such as the crash of the whole vehicle, the protection of the battery can still be useful. In the selection of battery barriers, manufacturers are also fully aware of the importance of choosing barriers with self-maintenance functions. Now, general high-quality lithium-ion battery products have already used this technique. The use of maintenance equipment for preventing overchargers has long become a national mandatory standard. Qualified electronic maintenance equipment and mature battery pack management system have greatly reduced the probability of spontaneous combustion of lithium-ion batteries in new energy cars. Judging from the current cases that lead to spontaneous combustion of new energy cars, none of them are caused by spontaneous combustion and explosion of battery packs under normal driving conditions. More explosions and spontaneous combustion of lithium-ion batteries in new energy cars come from extremely serious traffic accidents and improper modification of electrical equipment in the car. The lithium-ion battery was finally ignited under the high temperature of nearly a thousand degrees. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: What kinds of materials are used for lithium-ion batteries